How would I write a regex style rule that fires when it encounters a question mark in a name?

There is a group of local mappers that have used an invented name of "Ban ?" for towns they do not know the name of. I want to set the name to something more meaningful but I can't seem to discover a way to escape the ? without crashing mkgmap.

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Dave Swarthout
Homer, Alaska
Chiang Mai, Thailand
Travel Blog at http://dswarthout.blogspot.com